Lemurs are a primitive group of primates which survive now only on the island of Madagascar, which was isolated from Africa 50 million years ago. There are no monkeys on Madagascar, which would otherwise have provided too much competition for the lemurs to survive. Since man arrived in Madagascar about 2000 years ago, he has caused great destruction of nature, through deforestation and overhunting. 30 species of lemur survive, some very rare now, but a further 14 species have become extinct at the hands of man.